I0I4 LIFE : OUTLINES OF GENERAL BIOLOGY 



non-rotated rats, and these showed the two kinds of locomotor 

 disorder that marked the rotated rats and their offspring according 

 to the direction of the whirhng, whether clockwise or counter clock- 

 wise ! Dr. Detlefsen does not set himself to explain away the results 

 of the experiments made by Drs. Bentley and Griffith; he merely 

 indicates a possible fallacy. And that is sound science. 



One other instance must suffice, for our present point is simply to 

 illustrate the difficulty of getting a clear issue. Prof. M. F. Guyer 

 and Dr. E. A. Smith injected into fowls a salt solution of pulped 

 rabbit-lens, to which the blood-serum of the fowl reacted, developing 

 lens-antibodies — that is to say, counteractives to the intruded 

 substance. Some of the fowl-serum was then injected into female 

 rabbits with young. Of the sixty-one surviving offspring of these 

 rabbits four had one or both eyes conspicuously defective, especially 

 as regards the lens, and five others had eyes that were clearly 

 abnormal. The lens-antibodies in the blood produced specific eye- 

 defects in the embryos — defects which no other mode of treatment 

 ever produced. But the striking fact is that once the defect has 

 arisen, it may be transmitted to subsequent generations (as many as 

 nine) through breeding. The descent has been repeatedly established 

 through male as well as female lines. The abnormal condition has in 

 general the characteristics of a Mendelian recessive; i.e. a defective- 

 eyed rabbit bred to a normal-eyed rabbit has only normal-eyed 

 progeny in the first generation. 



Here then is a very remarkable case. Developing embrj^os were 

 specifically modified in their early ante-natal life by the influence of 

 an antibody introduced into their parent's blood, and this specific 

 modification was handed on to subsequent generations, and by males 

 as well as by females. It may be, however, as Prof. Guyer points out, 

 that the germ-cells of the original offspring were specifically affected 

 at the same time as the eyes, and that the lens-producing constituents 

 in these germ-cells were specifically damaged. This would be what 

 is technically called "parallel induction" rather than the trans- 

 mission of a somatic modification. It is interesting to find that the 

 eye-defects may increase from generation to generation, which looks 

 as if the deteriorated eye could originate chemical substances 

 in the blood which repercuss deterioratively on the germ-cells. In 

 any case, it is clear that the germ-cells do not live a charmed life, 

 uninfluenced by the turmoils that ma}^ be set up in the body. 



Some of the recent experiments, such as Kammerer's, seem to us 

 to suggest an affirmative answer; others, such as Agar's, seem to us 

 to suggest a negative answer; none seem to us to be definitely 

 conclusive — not even Kammerer's until more details are forth- 

 coming. Why should we hurry, except for more facts? We should 

 not like to be responsible for Herbert Spencer's two alternatives — 

 "either there has been inheritance of acquired characters, or there 



